Final answer:
The most appropriate measure to teach the parent of a nine-month-old infant about diaper dermatitis is to avoid using occlusive ointments on the rash.
Step-by-step explanation:
Diaper dermatitis, or diaper rash, is a common condition in infants. When teaching the parent of a nine-month-old infant about diaper dermatitis, it is important to provide accurate information. Out of the given options, the most appropriate measure would be B) Do not use occlusive ointments on the rash. Occlusive ointments can trap moisture and worsen the rash. Instead, it is recommended to use a barrier cream that allows the skin to breathe.
Using cloth diapers rinsed in bleach (A) may be too harsh for the baby's sensitive skin and can cause irritation. Commercial baby wipes (C) may contain chemicals that can irritate the skin. Discontinuing a new food (D) would only be appropriate if there is evidence of a food allergy or intolerance.